TT Viruses in Animals
Infection with TT virus (Torque teno virus, TTV), a small, nonenveloped virus with a circular, single-stranded DNA genome classified in the floating genus Anellovirus , is not restricted to humans. Using highly conserved primers derived from the untranslated region of the human TTV genome, a variety of TTV-like viruses have been found circulating in nonhuman primates such as chimpanzees, macaques, and tamarins. TTV variants in nonhuman primates are species-specific, although some genetic groups of human and chimpanzee TTVs cluster to make human/chimpanzee clades. TTVs from macaques and tamarins are increasingly divergent from TTV variants infecting humans and chimpanzees. TTV-like mini virus (TTMV) infections have also been detected in chimpanzees, with genotypes distinct but interspersed with human TTMV genotypes. Pets are also naturally infected with species-specific TTVs, and several isolates have been found in cats and dogs. In addition, other mammals such as tupaias and pigs have species-specific TTVs: swine TTVs are found among pigs worldwide. The genomic organization and proposed transcriptional profiles of TTVs infecting nonhuman primate and other mammalian species are similar to those of human TTVs, and co-evolution of TTVs with their hosts has been suggested. To date, TTVs infecting nonhuman primates and other mammalian species have been under-examined. It is likely that essentially all animals are naturally infected with species-specific TTVs.
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- Allan GM, Caprioli A, McNair I, et al (2007) Porcine circovirus 2 replication in colostrum-deprived piglets following experimental infection and immune stimulation using a modified live vaccine against porcine respiratory and reproductive syndrome virus. Zoonoses Public Health 54:214–222PubMedCrossRefGoogle Scholar
- Biagini P, Todd D, Bendinelli M, et al (2005) Genus Anellovirus . In: Fauquet CM, Mayo MA, Maniloff J, et al (eds) Virus taxonomy: classification and nomenclature of viruses, eight report of the international committee on taxonomy of viruses. Elsevier/Academic Press, London, pp 335–341Google Scholar
- Kekarainen T, Segales J (2008) Torque teno virus infection in the pig and its potential role as a model of human infection. Vet J Feb 22 [Epub ahead of print]Google Scholar
- Martin RD (1990) Are tree shrews primates? In: Martin RD (ed) Primate origins and evolution: a phylogenetic reconstruction. Chapman and Hall, London, pp 191–213Google Scholar
- Okamoto H, Nishizawa T, Takahashi M, et al (2001a) Genomic and evolutionary characterization of TT virus (TTV) in tupaias and comparison with species-specific TTVs in humans and non-human primates. J Gen Virol 82:2041–2050Google Scholar
- Okamoto H, Nishizawa T, Takahashi M (2004) Torque teno virus (TTV): molecular virology and clinical implications. In: Mushahwar IK (ed) Viral hepatitis: molecular biology, diagnosis, epidemiology and control. Elsevier, AmsterdamGoogle Scholar
- Todd D, Bendinelli M, Biagigi P et al (2005) Family Circoviridae. In: Fauquet CM, Mayo MA, Maniloff J, et al (eds) Virus taxonomy: classification and nomenclature of viruses, eight report of the international committee on taxonomy of viruses. Elsevier/Academic Press, London, pp 327–334Google Scholar